Fix asterisk/manager.h detection

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4633 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fix compilation against asterisk-1.6.2

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4634 43c1dc8c-776e-4df2-8ef1-6e829299be21
Fix compilation against asterisk-1.6.2 (removed ast_sched_context_destroy which does not exist in this version)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4635 43c1dc8c-776e-4df2-8ef1-6e829299be21
Removal of do_monitor/restart_monitor funktions for asterisk version 10 and up (Lock issue reported by Niklas Larsson)

git-svn-id: https://svn.code.sf.net/p/chan-sccp-b/code/trunk@4636 43c1dc8c-776e-4df2-8ef1-6e829299be21